Completion of wells



May 1, 1962 R. c. RUMBLE ETAL COMPLETION OF WELLS ROM FIIRING PARAMAGNETIC 2 Sheets-Sheet l III 5-] FIRING 1 INDICATOR SWITCH 59 5 L R M B E MY m m R m W C A T R R E M B L mw V. B

Filed Nov. 28, 1958 FIRING FILAMENT A T TORNEY.

y 1962 R. c. RUMBLE ET AL 3,032,107

COMPLETION OF WELLS 2 Sheets-Sheet 2 Filed Nov. 28, 1958 \(LINE OF FIRE LINE OF FIRE \{LINE OF FIRE FIG. 5.

FIRING SWITCH A AMPLIFIER AND LEVEL SET GENERATOR INVENTORS. ROBERT C. RUMBLE, BY WILMER A. HOYER,

DETECTOR/ ATTORNEY.

3,032,107 COMPLETHON F WELLS Robert C. Rumble, Houston, and Wilmer A. Hoyer, Bellaire, Tex., assignors, by mesne assignments, to Jersey Production Research Company, Tulsa, Skin, :1 corporation of Delaware Filed Nov. 28, 1958, Ser. No. 776,398 8 Claims. (Q1. 166--55.1)

This invention relates generally to completion of wells in the earth, and more particularly to the perforation of parallel, mutually independent, eccentrically disposed pipe strings.

It is often desired to complete wells drilled through productive hydrocarbon-containing earth formations by lowering a plurality of eccentrically disposed, mutually independent pipe strings in a cased or uncased borehole, circulating cement through the pipe strings to bond the pipe strings to the casing or surrounding earth formations, and perforating the pipe strings and surrounding cement to permit the flow of hydrocarbons into the pipe strings. Only one of the pipe strings should be perforated for each of the producing formations penetrated by the borehole; if a perforating gun is randomly oriented in a pipe string, it will be quite probable that more than one pipe string will be perforated when the gun is fired. Manifestly, it is necessary to insure that the gun is aimed away from the other pipe string at the time that it is fired.

This invention contemplates the use of paramagnetic spacing means between pipe strings at or near depths in a well whereat a pipe string is to be perforated. Physically connected to the perforating means on the end of a wire line is detecting means for detecting the position of the spacing means relative to the pipe string to be perforated. The detecting means and perforating means may revolve together on the end of the wire line. The detecting means is adapted to energize actuating means for actuating the perforating means at the instant that the spacing means is detected. By suitably connecting together the detecting means and the perforating means, the perforating means may be made to perforate the pipe string within which is disposed and not to perforate other pipe strings in the borehole.

The detecting means may detect the spacing means by reluctance measurements from within the pipe string within which it is disposed. The paramagnetic spacing means will lower the apparent reluctance of the section of the pipe string at which it is afiixed so that a drop in reluctance will indicate the position of the spacing means. Apparatus for measuring reluctance may comprise a pair of vertically spaced, parallel magnetic means spaced apart at the center thereof by paramagnetic connecting means so as to form a pair of closed magnetic loops having a common flux path through the connecting means. When the reluctance of the flux path across the ends of the magnetic means is equal, the flux in the connecting member eifectively will cancel. This condition may obtain when the magnetic means is arranged in a pipe string so that the reluctance presented by the pipe string is equal at both ends of the pair of magnetic means. When one end of the magnetic means is adjacent a paramagnetic spacer, there will be an unbalance in the magnetic circuit including the paramagnetic spacer that will result in a net flux in the connecting member. By detecting this net flux and actuating the perforating means when at least a predetermined net flux is passing through the connecting member, the pipe string can be perforated in a direction away from the other pipe strings in the borehole.

While the apparatus will afford an indication of the direction of the casing strings adjacent the string in which the device is suspended without the use of the paramag- States Patent netic spacer, the accuracy of the apparatus is enhanced and its operation is simplified when the spacer is used.

This invention will be more completely described with reference to the accompanying drawing, wherein:

PEG. 1 is a side view, partially in cross-section, of an embodiment of the invention;

FIG. 2 is a fractional side view, partially in cross-section, of the spacer detecting means shown in FIG. 1;

FIG. 3 is a sectional view taken along section 3-3 of FIG. 2;

FIG. 4 is a schematic diagram of an electrical gun-actuating circuit suitable for use with the embodiment of FIG. 1;

FIGS. 5, 6, and 7 illustrate other embodiments of the invention; and

FIG. 8 illustrates an electrical control and gun-actuating circuit suitable for use with the embodiment of the invention shown in FIG. 7.

With reference now to the embodiment of the inven tion illustrated in FIGS. 1 through 4, there is shown a pair of eccentrically positioned, mutually independent pipe strings 1 and 3 spaced apart in a borehole, shown here as an uncased borehole. The pipe strings are spaced apart by a paramagnetic spacing means 21, which may be metallic. It is assumed that cement has been circulated through one of the pipe strings so as to bond both pipe strings to the surrounding earth formations, and that: the pipe string has been cleaned with a suitable flushing fluid. Suitable procedures for this purpose are well known in the art and will not be described herein.

Perforating gun is attached to a detecting sonde 10 by means of a flexible joint 33. Both the sonde and the gun are suspended from a cable 5. The sonde may include a cable connector 7 at the upper end thereof for connection to the cable 5. The cable 5 may be a conventional multiconductor borehole logging cable and may include a plurality of electrical leads.

Gun 35 may be of conventional design and may include a plurality of shaped charges 37 electrically actuated by suitable firing filaments. The perforating gun is connected to the sonde through flexible joint 33 and hex head 31 so that the sonde and the gun will rotate together at the end of cable 5. The sonde and gun may be free to rotate on the end of the cable and may be rotated several turns clockwise and counterclockwise by changes in cable tension accompanying the raising or lowering of the apparatus. Other means for rotating the sonde and gun may be used.

Projecting through a port 27 in the sonde are pairs of magnetized members 15, 16, 17, and 18 joined together a brad or other suitable means 43. An electrical contact 47 is insulatively afiixed to pole piece 40 so that vane 45, when it rotates to a vertical direction, will engage contact 47 and complete an electrical circuit to the instrument housing through spring 44 and an electrical lead (not shown) attached from the spring to the body of the sonde It). An electrical lead 24 from contact 47 and electrical lead 23 extending to the earths surface, as described below, are connected to opposite ends of a firing filament in perforating gun 35 so that when vane 45 rotates to a vertical position, a circuit will be completed to actuate the firing filament when vane 45 rotates to a vertical position.

Magnetized members 15 and 17 may be positioned as shown in FIG. 2, with the north poles of magnetized members 15 and 16 to the left of the south poles thereof, and the south poles of magnetized members 17 and 18 to the left of the north poles thereof. The magnetized members may engage the inner surface of the well pipe 1 and may be lubricated if necessary to insure that the members will slide through the Well pipe. As will become evident upon consideration of FIG. 2, a pair of magnetic circuits are formed by this arrangement, the magnetic flux of one circuit passing from magnetized member 15, down well pipe 1, through the lower magnetized member 17, and up through pole pieces 40 and 38 and the air gap therebetween. The other magnetic path extends from magnetized member 16, down through pole piece 38, the air gap between pole pieces 38 and 40, pole piece 40, magnetized member 18, and up through the well pipe to magnetized member 16. When the reluctance offered by the well pipe to the passage of flux therethrough is the same for both magnetic paths, the magnetic flux through the pole pieces and air gap will be equal and opposite so as to effectively cancel. There will be no force exerted on vane 45 to counteract the efiect of spring 44. However, when the apparatus is adjacent a spacer 21 so that the reluctance to the passage of magnetic flux is altered, more flux will pass through the right-hand loop than will pass through the left-hand loop. A net flux will exist in the pole pieces and air gap that will rotate vane 45 to the vertical to engage contact 47.

FIG. 4 shows an electrical circuit that may be used with the embodiments of the invention shown in FIGS. 1, 2, and 3. As described above, vane 45 completes a circuit from switch contact 47 to the sonde housing 10 from firing filament 49. The firing filament may be of the type that fires a shaped charge when sufiicient current passes therethrough. An electrical lead 23, also connected to the firing filament, extends upwardly through one of the conductors of the logging cable to the earths surface. For the purpose of providing a surface indication when the apparatus is aligned with a spacer 21, an ammeter 61 is connected in series with a current limiting resistor 55, a battery or other direct current source 53, and a manually actuated indicator switch 59. When vane 45 is vertically positioned so as to engage contact 47, and when indicator switch 59 is closed, current will flow through the circuit and will be indicated by ammeter 61. However, this current will not be suflicient to actuate firing filament 49 inasmuch as current limiting resistor 55 limits the current to a safe value. When current flow is indicated by ammeter 61, firing switch 57 may be closed to energize firing filament 49 and actuate perforating gun 35.

Referring again to FIG; 1, it will be noted that electrical lead 23 passes through a circuit box 13 and a lead connector 9. The function of the circuit box may be to house suitable relays and a local source of electrical current when it is not desired to pass a large amount of current down through the logging cable. Apparatus of this nature is known to the art and will not be further described herein.

In FIG. 5 there is shown an embodiment of the invention that may be used effectively when more than two pipe strings are to be utilized in a borehole. Manifestly, should two spacer members be connected to a given well pipe as is necessary when three well pipes are to be spaced apart in a symmetrical configuration, the apparatus described in FIGS. 1 through 4 may be aligned with either of the spacer members to actuate the perforating means. The apparatus of FIG. 5 permits more accurate orientation than is possible with the apparatus of FIGS. 1 through 4 when three pipes are in a well.

In the embodiment of the invention shown in FIG. 5, it-is desirable to orient a gun within a well pipe 75 connected to well pipes 73 and 79 by spacer means 63 and 67, respectively. Two sets of magnetized members 71 and 69, each similar to the sets of dual magnetized members illustrated in FIGS. 1 through 3, are connected to a central connecting apparatus 81 which may be a pair of pole pieces, a non-magnetic connecting means, and a vane such as is shown in FIG. 2. The angle between the pole pieces 69 and 71 should be approximately 60 degrees so that they will line up fairly exactly with both of the spacer members 63 and 67. When the magnetized members are in any position other than that shown in FIG. 5, the magnetic flux through the air gap between the pole pieces will be insufficient to rotate the vane to engage the contact 47. However, when the pole pieces are in the position shown in FIG. 5, the total flux through the connecting members 81 will be sufficient to rotate the vane to the vertical to engage the contact and make it possible to complete the firing circuit.

FIG. 6 illustrates a modification of the invention that is useful when it has been found difficult to lower the spacer detecting apparatus through a pipe string without making the air gap between the pipe string and the magne-ts too large. Magnets 15 and 16 are attached obliquely to pole piece 38, and magnets 17 and 18 are attached obliquely to the pole piece with the magnets vertically spaced apart as shown in FIG. 2. A biasing means such as bow spring 83 also is affixed to the pole pieces, which spring should be of non-magnetic material. The angle between the bow spring and the magnets should be such that both sets of vertically spaced magnets are urged against the sides of the pipe by the bow spring. Typically, where the acute angle between the magnets is approximately 60 degrees, the angle between the spring and the individual magnets may also be 60 degrees. When the apparatus is lowered through a well pipe, the spring will yield to irregularities in the pipe so that the magnets may touch the pipe without danger of binding the apparatus therein.

In all of the embodiments described above, the perforating gun should be positioned so that the line of fire is directed away from the other pipe strings in the borehole when the magnets are aligned with the spacer means. Suitable lines of fire are indicated in FIGS. 3, 5, and 6, but it is to be understood that other lines of fire may be utilized.

The embodiment of FIGS. 7 and 8 utilizes a balanced coil arrangement rather than the permanent magnet array described in the embodiments of the invention illustrated in FIGS. 1 through 6. Paramagnetic co-res 85, 87, 89, and 91 are respectively provided with energizing coils 93, 95, 99, and 97, which are serially conccted so that flux will pass through cores 85 and 87 in one direction and through cores 91 and 89 in the other direction. The leads C and D from the coils are connected to alternating current generator 107 which may have a frequency of approximately 400 cycles. Core members 85 and 87 are spaced apart from core members 89 and 91 by a paramagnetic connecting member 101. A pickup coil 103 is wound on paramagnetic connecting member 101. The output leads A and B of the coil 103 are connected to an alternating current amplifier 105, the output signal from which is connected to a detector 109. The core members and the associated energizing coils are wound so that no net magnetic flux will be in the connecting member 101 except when the cores are in line with a spacing member between pipe strings. The alternating flux set up in the connecting member will induce an output signal in the pickup which may be amplified and detected by amplifier 105 and detector 109.

When indicator switch 59 is closed, current from D.C.

source 53 will flow through resistor 55 and ammeter 61, through electrical lead 60, through contact 119 of relay 121, and through the actuating coil of the relay. The relay will be actuated so that coil 115 will be connected through contact 120 to a local D.C. source 122' and through contact 117 to ground. Relay 121 thus will be held in its actuated position.

After a suitable time delay determined by time delay means 113, alternating current generator 107 and amplifier 105 will be energized from local D.C. source 122. Time delay means 113 prevents premature heating of firing filament 49 when switch 59 is depressed. When an output signal appears across pickup coil 103, current will flow through coil 129 of relay 127. A circuit will be completed from lead 6%) through contacts 123 and 125 and through the firing filament to provide an indication on ammeter 61. Firing switch 57 thereupon may be closed to actuate the firing filament and detonate the perforating gun.

Several modifications of the invention have been de scribed by means of which a perforating means may be positively oriented with respect to pipe strings in a borehole other than the pipe string within which the perforating means is lowered. The invention provides a positive means of determining the position of the other pipe strings and of selectively actuating the perforating means when it is decided that the perforating means is properly positioned.

The invention is not to be restricted to the specific structural details, arrangement of parts, or circuit connections herein set forth as various modifications thereof may be effected without departing from the spirit and scope of this invention.

What is claimed is:

1. Apparatus for orienting and actuating a perforating means adapted to be suspended on a line in one of a plurality of pipe strings spaced apart at a given depth in a well by paramagnetic connecting means between pairs of pipe strings, comprising: an H-shaped member including first and second vertically-spaced, paramagnetic sections connected by a third paramagnetic section; an alternating current source; coil means wound on said first and second paramagnetic sections and electrically connected to said alternating current source, said first and second paramagnetic sections and the pipe string within which said coils are positioned defining a pair of closed magnetic loops having a common magnetic flux path through said third paramagnetic section, the magnetic flux in said third paramagnetic section included in the respective magnetic loops being in opposite directions; and circuit means independently coupled to said third paramagnetic section adapted to produce an alternating voltage when the magnetic fiux in the pairs of magnetic loops are not equal; actuating means adapted to actuate said perforating means upon energization thereof, and means electrically coupled to said circuit means adapted to energize said actuating means so as to actuate the perforating means, responsive to attainment of a given amplitude by said alternating voltage.

2. Apparatus for orienting and actuating perforating means adapted to be suspended on a line in one of a trio of pipe stings substantially symmetrically spaced apart at a given depth in a borehole by paramagnetic spacing means connected between the pipe strings, said apparatus comprising: two pairs of crossed magnetized members spaced apart by a paramagnetic connecting member connected between the crossing points thereof so that pairs of said members are parallel and vertically spaced apart by said paramagnetic connecting member; said paramagnetic connecting member providing a central flux path between said crossed magnetized members wherein magnetic flux passing therethrough will substantially cancel when the sides of said one pipe string.

offer substantially the same reluctance to magnetic lines of flux between said crossed magnetized members; each of said pairs of parallel spaced-apart members defining a pair of magnetic loops having oppositely directed flux paths through said connecting member, said pairs of crossed magnetic members being adapted to fit in a horizontal plane within a vertical pipe and contact the interior of the pipe; the acute angle between said pairs of crossed members being substantially 60, the portions of said members defining a given acute angle being magnetized in the same sense; electric circuit means adapted to actuate the perforating means upon energization thereof; and means connected to said circuit means magnetically coupled to said connecting member adapted to energize said electric circuit means when the net mag netic flux in said connecting member is greater than a predetermined amount.

3. Apparatus for orienting and actuating a perforating means in one of a plurality of pipe strings spaced apart at a given depth in a well by paramagnetic connecting means connected between the pipe strings, comprising: an electrical circuit for actuating said perforating means upon energization thereof; first and second pole pieces spaced apart by a non-magnetic sleeve; a paramagnetic vane pivotally supported between said pole pieces and adapted to rotate to an actuated position responsive to magnetic flux between said pole pieces, said vane being connected to said electrical circuit for energization thereof when said vane is in said actuated position; and magnetic means connected to said pole pieces adapted to set up first and second magnetic loops, each magnetic loop including a portion of the well pipe within which said pole pieces are disposed, the portions of the well pipe being circumferentially spaced apart; the flux in both magnetic loops passing through said first and second pole pieces and the air gap therebetween and being opposite in direction and substantially equal when said magnetic members are not aligned with a paramagnetic connecting means so as to include said paramagnetic spacing means in one of said magnetic loops; said vane being adapted to be swung into said actuated position when said paramagnetic spacing means is in one of said magnetic loops.

4. Apparatus as defined in claim 3 wherein biasing means are connected to said pole pieces to urge said magnetic means into engagement with the inner wall of a well pipe.

5. Apparatus for orienting and actuating a perforating means in one of a plurality of pipe strings spaced apart at a given depth in a well by paramagnetic spacer means positioned between the pipe strings, comprising: magnetic means, including magnetic flux producing means, adapted to be connected to the perforating means for rotation with said perforating means around the longitudinal axis of one of the pipe strings at the end of a line in said one of the pipe strings; said magnetic means defining a magnetic circuit that is normally balanced, and that is adapted to become unbalanced when the paramagnetic spacer means is in the magnetic field of said magnetic means; a normally open magnetically actuated electric switch coupled to said magnetic circuit, adapted to close responsive to unbalance in said magnetic circuit; and circuit means electrically connected to said switch adapted to actuate the perforating means responsive to closure of said switch.

6. Apparatus for orienting and actuating a perforating means adapted to be suspended on a line in one of a plurality of pipe strings spaced apart at a given depth in a well by paramagnetic spacer means: between pairs of pipe strings, comprising: actuating means connected to the perforating means adapted to actuate the perforating means upon energization of said actuating means; magnetized detecting means connected to said actuating means and to the perforating means for rotation in a horizontal plane in a pipe string with said perforating means, said detecting means being further adapted to detect the orientation of the paramagnetic spacer means relative to the pipe string within which the perforating means is suspended; and electrical energizing means connected to said detecting means responsive to detection by said detecting means of said paramagnetic spacer means to energize said actuating means whereby said perforating means is actuated.

7. Apparatus for orienting and actuating a perforating means in one of a plurality of pipe strings spaced apart at a given depth in a well by paramagnetic spacer means positioned between the pipe strings, comprising: magnetic means, including magnetic fiuX producing means, for connection to the perforating means and adapted to be suspended with the perforating means in one of the pipe strings at the end of a line; said magnetic means comprising spaced-apart magnetic members defining flux paths including two horizontally spaced-apart portions of said one pipe string, said magnetic means being adapted to be suspended from the line with the perforating means to permit rotation thereof in a horizontal panel normal to the longitudinal axis of said one pipe string", connecting means connecting together said magnetic means to provide a central flux path therebetween wherein the magnetic flux will substantially cancel when said portions of said one pipe string offer substantially the same reluctance to said magnetic lines of flux between said magnetic means; means, including electric switch means, magnetically coupled to said connecting means responsive to an increase in magnetic flux intensity in said connecting means to close said electric switch means; and circuit means electrically connected to said electric switch means adapted to actuate the perforating means upon closure of said electric switch means.

8. Apparatus for orienting and actuating a perforating means in one of a plurality of pipe strings spaced apart at a given depth in a well byparamagnetic spacer means positioned between the pipe strings, comprising: magnetized means adapted to be connected to the perforating means, and further adapted to be suspended in one of the pipe strings at the end of a line; said magnetized means comprising spaced-apart magnetic members defining flux paths including spaced-apart sides of said one pipe string, said magnetic means being adapted to be suspended from the line with the perforating means to permit rotation thereof in a horizontal plane normal to the longitudinal axis of said one pipe string; connecting means, including magnetizable means, connecting together said magnetic means to provide a central flux path therebetween wherein the magnetic flux will substantially cancel when said spaced-apart sides of said one pipe string offer substantially the same reluctance to said magnetic lines of flux between said magnetic members; electrical circuit means adapted to actuate said perforating means upon energization thereof; and means connected to said electrical circuit means and magnetically coupled to said connecting means adapted to energize said electrical circuit means when the net magnetic flux in said connecting means is greater than a predetermined flux.

References (lited in the file of this patent UNITED STATES PATENTS 

